import numpy as np
import pandas as pd
arr=np.arange(1,10).reshape(3,3)
df1=pd.DataFrame(arr,columns=['a','b','c'])
df1.insert(0,'key',['001','003','002'])
print('左对象原数据df1：\n',df1)
arr2=np.arange(10,14).reshape(2,2)
df2=pd.DataFrame(arr2,columns=['a','e'])
df2.insert(0,'key',['001','004'])
print('右对象原数据df1：\n',df2)
df3=pd.merge(df1,df2,how='left')
print('以具有相同标签的所有列左合并的数据df3:\n',df3)
df4=pd.merge(df1,df2,how='left',on='key')
print('以key列左合并的数据df4:\n',df4)
df5=pd.merge(df1,df2,how='right',on='key')
print('以key列右合并的数据df5:\n',df5)
df6=pd.merge(df1,df2,how='inner',on='key',suffixes=('_1','_r'))
print('以key列内合并，并设置附加后缀的数据df6:\n',df6)
df7=pd.merge(df1,df2,how='outer',on='key',sort=True)
print('以key列外合并，并按连接列排序的数据df7:\n',df7)
